Commit 16e0f188 authored by Eric Dumazet's avatar Eric Dumazet Committed by Greg Kroah-Hartman

netem: fix a use after free

[ Upstream commit 21de12ee ]

If the packet was dropped by lower qdisc, then we must not
access it later.

Save qdisc_pkt_len(skb) in a temp variable.

Fixes: 2ccccf5f ("net_sched: update hierarchical backlog too")
Signed-off-by: default avatarEric Dumazet <edumazet@google.com>
Cc: WANG Cong <xiyou.wangcong@gmail.com>
Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 5438c1a5
...@@ -650,14 +650,14 @@ static struct sk_buff *netem_dequeue(struct Qdisc *sch) ...@@ -650,14 +650,14 @@ static struct sk_buff *netem_dequeue(struct Qdisc *sch)
#endif #endif
if (q->qdisc) { if (q->qdisc) {
unsigned int pkt_len = qdisc_pkt_len(skb);
int err = qdisc_enqueue(skb, q->qdisc); int err = qdisc_enqueue(skb, q->qdisc);
if (unlikely(err != NET_XMIT_SUCCESS)) { if (err != NET_XMIT_SUCCESS &&
if (net_xmit_drop_count(err)) { net_xmit_drop_count(err)) {
qdisc_qstats_drop(sch); qdisc_qstats_drop(sch);
qdisc_tree_reduce_backlog(sch, 1, qdisc_tree_reduce_backlog(sch, 1,
qdisc_pkt_len(skb)); pkt_len);
}
} }
goto tfifo_dequeue; goto tfifo_dequeue;
} }
......
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